Abstract
In plants and algae, the organellar replication enzyme has not been identified. The mitochondrial replication enzyme in animals, DNA polymerase gamma, is not encoded by the genomes of Arabidopsis thaliana and Cyanidioschyzon merolae. Two genes encoding DNA polymerases having homology to Escherichia coli DNA polymerase I in the nuclear genome of C. merolae were found (termed PolA and PolB). We examined intracellular localization of PolA and PolB by immunoblotting analysis using plastids and mitochondria from C. merolae. These results suggested that PolA is localized to plastids and PolB is to plastids and mitochondria. The study by using GFP was consistent with this result. We measured enzymatic activity of PolA and PolB, as well as plastids of C. merolae and mitochondria, and compared these characteristics. We examined the expression of these polymerases in synchronized culture. This result suggested that PolB is involved in the replication of organellar genomes in C. merolae.
